Efficient dispersion analysis of guided waves in laminated composites and substrates

Abstract

Nondestructive testing of laminated composites and substrates involve matching observed and predicted dispersion characteristics of guided waves. These characteristics are quantified through dispersion curves (phase velocity versus frequency) and need to be computed for a large number of estimated structure and material property combinations. Given its central nature, we propose an efficient approach for computing the dispersion curves, leading to an order of magnitude savings in the computational cost. Our approach is based on conventionally used finite element semi-discretization through the depth, but with one significant modification: by using a specially designed set of complex-valued finite element lengths through the depth, we show that the dispersion curves can be obtained with a handful of elements per layer as opposed to larger number of traditional finite elements, resulting in large reduction in computational effort. In this talk, we present the formulation of the proposed complex-length finite element method and illustrate its efficiency through modeling wave dispersion in laminated composites and substrates. Finally, we introduce an inversion procedure developed around this method and demonstrate its effectiveness in characterizing plate structures using synthetic as well as real nondestructive testing data.